Single drive axle trucks with a tag axle are known for their lighter weight, improved fuel economy, low installation cost and reliability in operations over tandem drive axle configurations. The North American truck market, however, is dominated by the tandem drive axle configuration in part due to single drive axle trucks having a low resale value. The low resale value can be partly attributed to the high cost associated with converting a single drive axle truck to a tandem drive axle truck. Conversion costs can be high since current tag axles have a different profile and wheel equipment than the drive axle, thus requiring a retrofitter to discard the tag axle, the suspension bracketry and the wheel equipment and install a new drive axle, suspension bracketry and wheel equipment.
In light of the disadvantages of the prior art, it would be advantageous to convert a non-driven tag axle to a driven axle by re-using much of the original equipment of the vehicle. It would also be advantageous to provide the vehicle with a tag axle assembly and a driven axle assembly that have substantially identical profiles that they can be interchanged with one another. It would also be advantageous for a truck fleet owner to have the ability to purchase a single drive axle truck and then later convert it to a tandem drive axle truck for resale.